Situated in a large lakeside development, Aqua intersperses undulating balconies with flat glassy planes to create a wavy facade in keeping with its nautical theme.

FRANKFURT.- The jury of the Emporis Skyscraper Award has announced Aqua, an 81-story residential and hotel tower in Chicago, as the winner of the 2009 Skyscraper of the Year. The award, now celebrating its tenth year, is given annually to a building at least 100 meters tall and completed within the award year.

The second place winner is O14 in Dubai. Third place goes to The Met in Bangkok. All winners were selected from 305 eligible buildings completed worldwide in 2009.

Members of the jury praised Aqua for its fascinating shape, whose appearance changes dramatically depending on the perspective. It was also cited as a brilliant technical achievement for the precision of its construction, and lauded as an application of green design innovations to an extremely large building project.

Situated in a large lakeside development, Aqua intersperses undulating balconies with flat glassy planes to create a wavy facade in keeping with its nautical theme. Because each balconys perimeter varies slightly from the one below, the contractors (James McHugh Construction Co.) employed a flexible mold in coordination with GPS. The effect has been compared to a rippled curtain, or (according to its architect Jeanne Gang of Studio Gang Architects), to the striated limestone formations common to the Great Lakes region.

Aqua is the third-tallest building in the world designed by a woman - surpassed only by the two Emirates Towers in Dubai - and is currently the 40th tallest building in the United States. Aqua has a height of 249.7 meters (819.34 feet) measured from its main entrance on Upper Columbus Drive.

The developer Magellan Development Group, LLC has applied for LEED certification for Aqua. The buildings numerous green qualities include post-tensioning to minimize concrete volume; large slab overhangs on the facade areas which receive the most sunlight in the summer; low-e coated insulated glass in all windows; frit patterned glass at the railings to prevent bird strikes; light coatings on exposed concrete to avoid a heat island effect; and a vegetated roof at the podium level. The firm of Magnusson Klemencic Associates served as Aquas structural engineers.

The Silver Award goes to O14 in Dubai, designed by Reiser + Umemoto Architecture. O14, whose unusual name is taken from its lot number in the massive Business Bay development, is an office tower wrapped in a curved concrete sheath punctuated by circular holes of varying sizes. The shell forms a shield against the powerful sunlight in the Arabian desert.

The Bronze Award goes to The Met in Bangkok, a 69-story residential tower incorporating multiple green features and optimized for energy-efficient comfort in a tropical climate. The Met was designed by WOHA Architects, whose Newton Suites in Singapore won second place in the 2007 Emporis Skyscraper Awards.